Alright, let’s do this properly
Below is a realistic mock thesis defense Q&A based on your study. These are the exact types of questions panels love to ask—from easy warm-ups to the tricky “testing-your-understanding” ones. I’ll also give you model answers you can deliver confidently as an undergraduate.
Thesis: Optimization of In Vitro Callus Induction in Aquilaria malaccensis Using Different Plant Growth Regulator Combinations
A. Opening / General Understanding
Q1. In simple terms, what is your study all about?
Suggested Answer:
My study focuses on developing an efficient in vitro protocol for inducing callus in Aquilaria malaccensis by testing different combinations of plant growth regulators. The goal is to identify which treatment produces the highest callus induction rate, fastest response, and best callus quality, which is important for conservation and future biotechnology applications.
Q2. Why did you choose Aquilaria malaccensis as your study species?
Suggested Answer:
Aquilaria malaccensis is an economically valuable but endangered species due to overharvesting for agarwood. Developing tissue culture techniques such as callus induction can support conservation, sustainable propagation, and future research, making it both scientifically and practically relevant.
B. Conceptual / Theoretical Questions
Q3. What is callus and why is it important in plant tissue culture?
Suggested Answer:
Callus is an unorganized mass of dedifferentiated plant cells formed when explants are cultured under appropriate conditions. It is important because it serves as a starting material for somatic embryogenesis, organogenesis, genetic transformation, and secondary metabolite production.
Q4. Why are plant growth regulators essential for callus induction?
Suggested Answer:
Plant growth regulators control cell division and differentiation. Auxins promote cell dedifferentiation and proliferation, while cytokinins enhance cell division and influence callus quality. The balance between these regulators determines whether callus will form and how actively it will grow.
C. Methodology-Focused Questions
Q5. Why did you use Murashige and Skoog (MS) medium?
Suggested Answer:
MS medium is widely used in plant tissue culture because of its high nutrient content, especially nitrogen, which supports rapid cell growth. It has been proven effective for many woody plant species, making it suitable for Aquilaria malaccensis.
Q6. Why did you choose 2,4-D and NAA as auxins?
Suggested Answer:
2,4-D is a strong synthetic auxin commonly used for callus induction because it promotes dedifferentiation. NAA is a milder auxin that supports callus growth when combined with cytokinins. Comparing these allows us to evaluate both strong and moderate auxin effects.
Q7. Why was the culture kept under dark conditions?
Suggested Answer:
Dark conditions favor callus induction by reducing differentiation and promoting cell dedifferentiation. Light can stimulate organ formation, which is not desired during the callus induction stage.
D. Results-Based Questions
Q8. Why did auxin-dominant treatments result in higher callus induction?
Suggested Answer:
Auxins stimulate cell division and dedifferentiation, which are essential for callus formation. Higher auxin concentrations promote continuous cell proliferation, especially in woody species like Aquilaria malaccensis.
Q9. Why is friable callus preferred over compact callus?
Suggested Answer:
Friable callus has loosely arranged cells, making it more suitable for regeneration, cell suspension cultures, and genetic manipulation. Compact callus is denser and less responsive in subsequent culture stages.
Q10. What does callus color indicate?
Suggested Answer:
Light-colored callus indicates healthy, actively dividing cells, while browning often results from phenolic oxidation and indicates stress or reduced viability.
E. Statistical & Experimental Design Questions
Q11. Why did you use a Completely Randomized Design (CRD)?
Suggested Answer:
CRD is appropriate because all experimental units were subjected to uniform laboratory conditions. Randomization minimizes bias and allows reliable comparison among treatments.
Q12. Why did you use ANOVA for data analysis?
Suggested Answer:
ANOVA is used to determine whether there are statistically significant differences among the means of multiple treatments. Since the study involved more than two PGR treatments, ANOVA was the most appropriate method.
F. Limitations & Critical Thinking
Q13. What are the limitations of your study?
Suggested Answer:
The study focused only on callus induction and did not evaluate regeneration potential, genetic stability, or biochemical properties. Additionally, results were obtained under controlled laboratory conditions, which may differ from field responses.
Q14. What would you improve if given more time and resources?
Suggested Answer:
I would evaluate somatic embryogenesis or shoot regeneration from the callus and assess genetic stability using molecular markers. I would also test anti-browning treatments to further improve callus quality.
G. Application & Future Work
Q15. How can your results be applied in real life?
Suggested Answer:
The optimized callus induction protocol can be used as a foundation for mass propagation, conservation programs, and future biotechnology applications such as genetic improvement and agarwood-related research.
Q16. Can this protocol be used commercially?
Suggested Answer:
At its current stage, the protocol is suitable for laboratory-scale research. Further optimization, scaling up, and regeneration studies are required before commercial application.
H. “Panel Favorite” Tricky Questions
Q17. If no callus formed in a treatment, does it mean the PGR is ineffective?
Suggested Answer:
Not necessarily. The PGR concentration or combination may not be optimal for that explant type or species. It may still be effective under different conditions or concentrations.
Q18. Why is optimization important instead of using published protocols?
Suggested Answer:
Plant response to tissue culture varies due to genotype, explant source, and environmental conditions. Optimization ensures that the protocol is effective for the specific species and laboratory conditions used in the study.
FINAL DEFENSE TIP (Very Important)
If you don’t know an answer, say:
“That aspect was beyond the scope of my study, but based on existing literature…”
Panels respect honesty + awareness of scope more than guessing.